For those who take an interest in this:

The accuracy statistics in Far Cry 2 are somewhat flawed.

For example, shotgun shots fire six (IIRC) pellets, where each counts as one fired bullet. If one of these kills, the remaining five don't count towards the accuracy statistics. So shotguns automatically lower them.

On the other hand, a hit with any rifle that kills *two* enemies at the same time counts as one bullet fired but two bullets hit - so you can raise your accuracy statistics. In fact you can rise it well beyond 100% - I think I have a savegame where I am at 140+%.

If you want to know your actual hit count (which you don't see), use this formula:
(bullets fired) x (accuracy per cent, read: divide by 100) = (actual hits).

If you want to know how many times you must score two kills per bullet to improve accuracy to 100%, simply subtract the actual hits from your total bullets fired: this is the number you need to score two kills per bullet to reach 100% accuracy.
The difference is obviously also the number of shots that missed.

Note: Explosives don't count - neither as shots fired nor towards kills. So use the grenade launcher and the crossbow to dispose of singular enemies and use only rifles to kill two at once.